I love my Quattros, but I have nothing else to compare them to because they are the only pedals I've ever tried. I generally do not have trouble clipping in, but sometimes my right foot does give me some trouble. My left foot "knows" exactly where the sweet spot is, but sometimes my right foot gets a little confused. Have you tried pointed your toe downwards when you're trying to clip in? Usually I can feel when the edge of the cleat has hit up against the spindle part. Then I just rock my foot back and it engages right away.

Also, are you sure that the cleats are tightly screwed into your shoes? This is my one complaint with the Quattros. I check my cleats before every ride because the screws tend to loosen up quickly. This may be a function of my specific shoes and how they interface with the cleat and surrounding tread plate thing-a-ma-bob. But if they are loose at all, it is virtually impossible to get clipped and unclipped.

Also, yes, the spindle part on my Quattros is a little more difficult to turn than I had expected. However, I think I'd rather have it this way than if it spun freely. If it turned more easily, it seems like it could spin away from the cleat every time you tried to clip in.

Good luck!